Wood Stoves & Fireplaces: What does "EPA Exempt" mean?

Q: I am looking at high-efficiency zero-clearance wood fireplaces and have run across one (Napoleon NZ6000) that, rather than claiming to be EPA-phase II approved, states that it is "EPA certification exempt."

What does this mean?

One dealer told me it was because the product was manufactured in Canada, but I suspect this is wrong as another similar product (NZ26) in the same line is EPA-approved.

Is it because the product is not a true wood stove?

Does the exemption imply that the efficiency does not meet EPA standards?

Thanks for any help you can provide. No one seems to know the straight answer, and I cannot find it online.

Sherwood

A: The Napoleon NZ6000 is not exempt from EPA regulations because it is made in Canada. All wood-burning heaters sold in the US are subject to EPA regulations, regardless of where they're built. However, the EPA regulations do allow for exemptions (wood-burners not required to meet today's strict particulate emissions standards).

Exempted products include wood cookstoves, as well as non-airtight fireplaces. To qualify for the non-airtight exemption, a fireplace must meet the EPA's definition, which requires a constant air-fuel ratio inside the firebox of at least 35-1. To maintain this ratio, the fireplace must allow a virtual free flow of air into the firebox. This airflow carries up to 90% of the heat from the fire up the flue, which is why exempted wood-burners tend to fall into the "just for looks" category.  Evidently, the NZ6000 is one of these (as evidence, the  emissions rating column in the installation manual  says N/A)

So, if exempted fireplaces are just for looks, why does Napoleon seem to be presenting the NZ6000 as heater, producing up to 60,000 btu/hr? In a word, marketing. The NZ6000's 4.8 cu.ft. firebox holds nearly 100 lbs. of average-density wood, and a raging wood fire of that size can produce a lot of heat: enough to provide meaningful warmth into the room despite the tremendous heat loss out the flue caused by the non-airtight design. The capability of providing up to 60,000 btu into the room from a 100 lb. load is actually not bad, for an exempted, non-airtight fireplace, but is a far cry from efficient wood heating. To put this in perspective, the EPA Approved Hearthstone Montgomery fireplace's 2.5 cu.ft. firebox holds just 50 lbs. of fuel, yet produces up to 75,000 btu/hr.

 Napoleon's literature states that they were able to achieve a 14-hour burn, which might imply that the NZ6000 has a controlled-combustion firebox, but that is not the case. Burn time figures can be misleading: a manufacturer can use one of the super-high-density wood species for this test (the NZ6000's 4.8 cu.ft. firbox will hold 270 lbs. of Osage Orange), and if any hot coals can be raked out of the ashes 14 hours later, the brochure can advertise a 14 hour burn. And you can bet that the advertised 60,000 btu maximum output was NOT achieved during the burn time test: note the "regular refueling" Napoleon mentions in the fine print linked to their heat output claim.

The bottom line? If you're looking for a fireplace with a big view of the raging fire, and want to get at least some heat from your 100-lb loads of wood, the NZ6000 is worth a look. If your goal is to heat your house with wood, an EPA approved stove or fireplace would save you much fuelwood, and be much kinder to the environment.

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Click to read the actual text of the EPA wood stove emissions regulations.